<button type="button" class="btn-prev" *ngIf="dir === 'left'" [class.disabled]="disabled" (click)="clickHandle(-1)"> 
    <i class="el-icon el-icon-arrow-left"></i> 
</button> 
<button type="button" class="btn-next" *ngIf="dir === 'right'"
    [class.disabled]="disabled" (click)="clickHandle(1)"> 
    <i class="el-icon el-icon-arrow-right"></i> 
</button>